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Differential pressure sensor / transmitter · BACnet points list
Dwyer Series MSX-Comms Magnesense Pressure Transmitter BACnet points list
Updated 4 November 2026
The MSX-Comms is a differential pressure transmitter for building air systems that can also calculate velocity or duct flow. Over BACnet MS/TP it reports the pressure in four units, velocity and flow, high and low alarm states, and exposes the process mode, K factor, duct area, alarm limits, damping and a zero calibration command.
This page lists 20 BACnet objects for the Dwyer Series MSX-Comms Magnesense Pressure Transmitter — 7 of them writable — with each object’s type, instance number, name, engineering units and access. It is re-typed from Dwyer’s own free documentation, linked below.
- Manufacturer
- Dwyer
- Model
- Series MSX-Comms Magnesense Pressure Transmitter
- Equipment
- Differential pressure sensor / transmitter
- Equipment type
- Thermostats, sensors & meters
- BACnet objects
- 20 (7 writable)
- Transport
- BACnet MS/TP
- Firmware
- Not stated
- Default device instance
- 607XXX (XXX = DIP switch address)
- Also known as
- MSX, MSX-Comms, Magnesense MSX, DwyerOmega MSX, MSX BACnet
Reference only, provided as-is: verify against Dwyer’s current documentation and the live device before use. Not official Dwyer information. Terms of use.
BMS integration notes: Dwyer Series MSX-Comms Magnesense Pressure Transmitter
Read the pressure AI in the unit you want, or the velocity/flow AV if the process mode is set to velocity or flow, and map the two alarm status BVs. Set MSV 1 Process Mode, the K factor and duct area once at commissioning.
Minimum points to map
The short list most integrators start with — enough to run the unit from a BMS. Map more as the job needs.
| Object | Name | Why | Access |
|---|---|---|---|
| AI 1 | Pressure inWC | Differential pressure, inWC | Read |
| AV 1 | Velocity FPM | Velocity, fpm (velocity mode) | Read |
| AV 3 | Flow CFM | Duct flow, cfm (flow mode) | Read |
| BV 6 | Alarm High Limit Status | High limit alarm active | Read |
| BV 8 | Alarm Low Limit Status | Low limit alarm active | Read |
Network setup
- BACnet MS/TP or Modbus RTU on RS485; baud, parity and stop bits are detected automatically from bus traffic.
- MAC address (0-127 for BACnet) is set on the DIP switches and also forms the device instance 607XXX.
- DeviceCommunicationControl and ReinitializeDevice need the password given in the manual.
Watch out for
- Write BV 2 Zero only with atmospheric pressure on both ports.
- Velocity and flow need the K factor (AV 5) and duct area (AV 6) set correctly.
Dwyer Series MSX-Comms Magnesense Pressure Transmitter BACnet objects
Type: AI, AO, AV, BI, BO, BV, MI/MO/MV (multi-state) · Access: Read read-only, Write writable, Command writable with a priority array.
| Description | States | |||||
|---|---|---|---|---|---|---|
| AImin | 1 | Pressure inWC | Differential pressure | inWC | Read | |
| AI | 2 | Pressure Pascals | Differential pressure | Pa | Read | |
| AI | 3 | Pressure Kilo-Pascals | Differential pressure | kPa | Read | |
| AI | 4 | Pressure mmWC | Differential pressure | mmWC | Read | |
| AVmin | 1 | Velocity FPM | Calculated velocity | fpm | Read | |
| AV | 2 | Velocity MPS | Calculated velocity | m/s | Read | |
| AVmin | 3 | Flow CFM | Calculated flow | cfm | Read | |
| AV | 4 | Flow CMH | Calculated flow | m³/h | Read | |
| AV | 5 | Velocity K Value | Velocity K factor, 0.001-9.999 | Write | ||
| AV | 6 | Flow Area SqFt | Duct area for flow, 0.125-25 ft² | ft² | Write | |
| AV | 8 | Flow Area SqM | Duct area in m² | m² | Read | |
| AV | 9 | Alarm High Limit | High alarm limit, unit of selected mode | Write | ||
| AV | 10 | Alarm Low Limit | Low alarm limit, unit of selected mode | Write | ||
| BV | 2 | Zero | Set Active (1) to run a zero calibration | Write | 0=Inactive, 1=Active | |
| BV | 5 | Alarm High Limit Enable | Read | 0=Inactive, 1=Active | ||
| BVmin | 6 | Alarm High Limit Status | Read | 0=Inactive, 1=Active | ||
| BV | 7 | Alarm Low Limit Enable | Read | 0=Inactive, 1=Active | ||
| BVmin | 8 | Alarm Low Limit Status | Read | 0=Inactive, 1=Active | ||
| MV | 1 | Process Mode | What the transmitter calculates | Write | 1=Pressure, 2=Velocity, 3=Flow | |
| PIV | 1 | Damping Time | Output damping | s | Write |
No points match these filters.
Object ID lookup: Dwyer MSX-Comms point IDs by name
AI1Pressure inWCAI2Pressure PascalsAI3Pressure Kilo-PascalsAI4Pressure mmWCAV1Velocity FPMAV2Velocity MPSAV3Flow CFMAV4Flow CMHAV5Velocity K ValueAV6Flow Area SqFtAV8Flow Area SqMAV9Alarm High LimitAV10Alarm Low LimitBV2ZeroBV5Alarm High Limit EnableBV6Alarm High Limit StatusBV7Alarm Low Limit EnableBV8Alarm Low Limit StatusMV1Process ModePIV1Damping Time
Integration notes
- Device instance and name are 607XXX / "MSX 607XXX", where XXX is the address set on the DIP switches. Object instances (AI 1, AV 1 ...) are fixed.
- Names follow the Object_Name defaults on the object pages; the summary table prints slightly different labels (for example "Pressure in w.c", "Flow Area sq ft").
- Access is from the "Is (User) Writable" column. That column marks AV 5, AV 6 and BV 2 as not writable, but the text says AV 5/AV 6 are set over BACnet and BV 2 is written to zero the sensor, so they are shown as W. The alarm enables BV 5/BV 7 are printed not writable and kept as R.
- AV 7, BV 1, BV 3 and BV 4 are not in the list. AV 9/AV 10 use the unit of the selected process mode.
Check it against the live device. A points list tells you what the controller can expose; the unit in front of you may differ by firmware or installed options. This list is provided as-is for reference only and may contain mistakes — confirming it before you write, map or commission anything is up to you (terms). Easy BACnet scans a network for BACnet IP devices from an Android phone, reads every object on the Series MSX-Comms Magnesense Pressure Transmitter and exports what it actually has to Excel — free. New to BACnet? Start with what a BACnet points list is and what the object types mean.
Questions about the Dwyer Series MSX-Comms Magnesense Pressure Transmitter
How many BACnet points does the Dwyer Series MSX-Comms Magnesense Pressure Transmitter have?
This list has 20 BACnet objects: 4 analog inputs, 9 analog values, 5 binary values, 1 multi-state value, 1 positive integer value. The exact set on a given unit depends on its firmware, installed options and configuration.
Which Dwyer Series MSX-Comms Magnesense Pressure Transmitter BACnet points are writable?
7 of the 20 objects accept a write. Points marked Command have a priority array: a write holds until it is released, so release it back to automatic when you are done.
Where is the official Dwyer Series MSX-Comms Magnesense Pressure Transmitter BACnet documentation?
The source is Series MSX-Comms Magnesense Pressure Transmitter, Installation and Operating Instructions (Bulletin P-MSX-C), published free by Dwyer at https://assets.dwyeromega.com/manuals-do/MSX_Instruction_Manual_(BACnet_Modbus).pdf.
What are the minimum BACnet points to integrate the Dwyer Series MSX-Comms Magnesense Pressure Transmitter?
Start with AI 1 Pressure inWC (Differential pressure, inWC); AV 1 Velocity FPM (Velocity, fpm (velocity mode)); AV 3 Flow CFM (Duct flow, cfm (flow mode)); BV 6 Alarm High Limit Status (High limit alarm active); BV 8 Alarm Low Limit Status (Low limit alarm active).
How do I check these points on the real Series MSX-Comms Magnesense Pressure Transmitter?
Scan the network with a BACnet IP browser such as Easy BACnet, open the device and compare its object list with this table. Anything missing is usually an option that isn't installed or a point that is disabled in the controller's configuration.
More Dwyer BACnet points lists
- CO2, humidity and temperature room sensor
Dwyer Series CDTA / CDTC Communicating CO2 Detector
Dwyer Series CDTA (CO2, humidity, temperature) and CDTC (CO2, temperature) wall-mount detectors with setpoint and override, BACnet MS/TP or Modbus RTU.
Also known as: CDTA, CDTC, CDTA-2N000, CDTA-5N000, CDTC-2N000, CDTC-5N000, CDTA-2N000-LCD - Differential pressure and airflow sensor
Dwyer Series MS2 Magnesense II Differential Pressure Transmitter with BACnet (MS2-B)
Dwyer Series MS2 Magnesense II differential pressure transmitters with BACnet MS/TP (ranges up to 25 in. w.c.).
Also known as: MS2-B, MS2, Magnesense II, P-MS2-B - Room pressure monitor
Dwyer Series RSME / RSMC Room Status Monitor
Dwyer Series RSME/RSMC room status monitors (built-in differential pressure plus universal and external BACnet inputs) for isolation rooms, labs and cleanrooms.
Also known as: RSME, RSMC, Series RSME, Series RSMC, DwyerOmega RSME, Dwyer room pressure monitor - Ultrasonic BTU / energy meter
Dwyer Series TUF ultrasonic energy meter, BACnet MS/TP (TUF-B)
Dwyer Series TUF ultrasonic heating/cooling energy meters (TUF-150 to TUF-2000) ordered with BACnet MS/TP.
Also known as: TUF, TUF-B, TUF BACnet, Dwyer TUF BTU meter, DwyerOmega TUF
Source: Series MSX-Comms Magnesense Pressure Transmitter, Installation and Operating Instructions · Bulletin P-MSX-C. Object names, instances and units are reproduced as published; descriptions are our own.